Which is the weaker sex? : A study of the differential mortality of males and females in Australia

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MORTALITY OF MALES AND FEMALES IN AUSTRALIA

by

ALA N D. L OP E Z

A thesis submitted for the degree of Doctor of Philosophy

at the Research School of Social Sciences

Australian National University

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Scholar in the Department of Demography of the Research School of

Social Sciences at the Australian National University from January

1975 to November 1978.

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I wish firstly to express my gratitude to my supervisors,

Dr. Lado T. Ruzicka and Dr. Christabel M. Young, who gave freely of their

time and expert knowledge in guiding this research. I am also grateful

to Dr. Lincoln Day of the Department of Demography, Australian National

University, for his many helpful suggestions on an earlier draft of

Chapter 8 of this thesis. 1 was fortunate to have a number of most

useful discussions with my colleague, G.L. Dasvarma, who is currently

completing a study on other aspects of differential mortality in Australia.

I am indebted to Anne Sandilands for her generous assistance

with the computer programs and especially for the production of the

computer listings given in Appendix C. I would also like to sincerely

thank Pat Mooney and Barbara Addison for typing the first draft and for

their magnificent effort in editing the final copy. My thanks also go

to Diane Shepherd for typing the final draft.

Finally, I would like to say thank you to mv colleague Lene

Mikkelsen for her constant help and encouragement, especially during

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ABSTRACT

During the course of the 20th century, mortality patterns in the

developed countries have been characterized by a persistent widening of

the gap in survival between the sexes. From a female advantage in longevity

at birth of about two to three years around the turn of the century, the

sex differential in many countries has increased to the point where females

now enjoy an expected lifespan of six to seven years more than that of

males. This thesis has been an investigation of the widening sex mortality

differential in Australia, with some historical reference to mortality

patterns during the colonial period. Almost one-half of this trend can be

accounted for by differential mortality changes for the sexes at ages 65

years and over, with a significant contribution from mortality differentials

at ages 15-64 years as well. Conversely, declines in mortality during

infancy and early childhood worked to the relative benefit of males. At

the older ages at least, much of the male disadvantage has arisen due to

their excess mortality from coronary heart disease, malignant neoplasms of

the lung, and the obstructive airways diseases, bronchitis, emphysema, and

asthma. For younger males, especially those aged 15-24 years, motor

vehicle accident mortality has been the leading determinant. A review of

international sex mortality differences confirmed that this was largely

consistent with the experience of other Western nations. Moreover, the

gap in survival between the sexes in Australia currently ranks among the

highest in the world, although there is now some evidence of a stabilization

of the sex mortality pattern during the 1970s. Biological differences have

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evidence strongly suggests that differential lifestyles between the

sexes were of far greater significance. It would appear that much of

the excess male mortality from the major degenerative diseases implicated

in this trend lias been due to their excess cigarette consumption, while

alcohol abuse has undoubtedly played a major role in the higher death

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LIST OF T A B L E S

Leading causes of excess male mortality, United States, 1967

Classification of Australian mortality statistics according to the Revisions of the International List of Causes of Death

Comparability ratios for selected causes of death according to the Seventh and Eighth Revisions of the International Classification of Diseases, Injuries and Causes of Death

Deaths from ill-defined and unknown causes (includ ing senility) as a percentage of all deaths by sex and age groups for selected censal periods in Australia

Population composition of New South Wales according to sex and civil status, 1828-51

Population size and sex ratios, Australian Colonies (and later States), 1861-1911

Life expectancy for the sexes at selected ages according to early Australian life tables, 1856-66 to 1901-10

Differential life expectancy at birth for the sexes, Colonies and States of Australia, 1881-1910

Expectation of life at birth for the sexes in selected European countries, mid 19th and early 20th centuries

Age-sex-specific mortality in Victoria, 1870-72 to 1910-12

Percent age-cause of death contributions to mortality change in Victoria, 1870-72 to 1910-12

Sex-cause-specific mortality rates during late infancy and early childhood, Victoria, 1870-72, 1890-92, and 1910-12

Page

43

62

77-78

81

92

95

105

106

108

110

112

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C H A P T E R 5

13 Life expectancy, ex , at selected ages, Australia,

1901-10 to 1970-72 128

14 Components of the difference between male and female

life expectancies at birth, Australia, 1901-10 to

1970-72 133

15 Percent decomposition of the change in the sex

mortality differential according to age and cause of

death, Australia, 1910-12 to 1970-72 140

16a Proportionate contributions to the sex mortality

differential from the age marginals, Australia,

1910-12 to 1970-72 149

16b Proportionate contributions to the sex mortality

differential from the cause of death marginals,

Australia, 1910-12 to 1970-72 150

17 Percent contributions by age and cause of death to

the change in life expectancy at birth for both sexes

combined, Australia, 1910-12 to 1970-72 156

18 Proportion of all deaths attributed to various causes,

Australia, 1910-12, 1946-48 and 1970-72 159

19 Percent decomposition of the change in the sex mortality

differential according to age and cause of death,

Australia, 1932-34 to 1946-48 160

20 Sex-specific mortality rates from the major diseases

common to the first five years of life, Australia,

1910-12 to 1970-72 163

21 Component analysis of maternal mortality in Australia,

1932-34 to 1946-48 166

22 Sex differences in mortality from the major degenera

tive diseases within broad age groups, Australia,

1910-12 to 1946-48 168

23 Age-sex-specific mortality rates from cancer of the

respiratory system, Australia, 1910-12 to 1946-48 170

24 Age-sex-specific mortality rates from suicide,

Australia, 1910-12 to 1970-72 173

C H A P T E R 6

mortality differential, Australia, 1950-52 to 1970-72 182

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mortality differential, Australia, 1960-62 to 1970-72 186

28 Percent decomposition of the sex mortality differential

by cause of death, Australia, 1950-52 to 1970-72 190

29 Probability at birth of eventually dying from specified

causes of death, Australia, 1950-52 to 1970-72 197

30 Probability of eventually dying from selected causes of

death at specified ages, Australia, 1950-52 to 1970-72 201

31 Gain in expectation of life at birth due to elimination

of specified causes of death, Australia, 1950-52 to

1970-72 203

32 Gain in expectation of productive life due to elimination

of specified causes of death, Australia, 1950-52 to

1970-72 207

33 Percent change in the sex mortality differential due to

the elimination of specified causes of death, Australia,

1950-52 to 1970-72 209

34 Standardized loss of life potential at birth from

specified causes of death per 100,000 years of potential

future lifetime, Australia, 1950-52 to 1970-72 216

35 Leading causes of lost years of potential life between

ages 15 and 64 years, Australia, 1950-52 and 1970-72 220

36 Age-sex-specific mortality rates, Australia, 1950-52

to 1976 223

37 Polynomial regression coefficients from trend analysis

for sex mortality ratios, certain respiratory diseases,

Australia, 1950 to 1976 227

C H A P T E R 7

38 Life expectancy at birth and the sex mortality different- 235

ial, selected nations, 1964

39 Percentage of deaths to persons aged 45 years and over

assigned to non-specific diagnoses, selected nations,

1971/72 241

40 Classification of nations according to sex mortality

patterns 243

41 Cluster analysis of sex mortality differentials

according to broad causes of death, selected nations,

1964 250

42 Average mortality characteristics of groups from the

cluster analysis based on absolute differences in death

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43 Sex-cause-specific mortality rates, selected nations, 1964

44 Trends in the sex mortality differential [e (f) - e (m)],

selected nations, 1910 to 1964

45 Percent contribution to sex mortality differentials from

specified age groups, selected nations, 1910, 1930, 1951 and 1964

46 Cause of death marginals from decomposition analysis of

sex mortality differentials, selected nations, 1910, 1930, 1951 and 1964

47 Percent contributions by cause of death to changes in

the sex mortality differential, selected nations, 1930-51, 1951-64, 1910-64

48 Percent contributions by cause of death to sex mortality

patterns in the United States, England and Wales, and New Zealand, 1910, 1965 and 1910-65

49 Standardized sex-cause-specific mortality rates for

selected causes of death, Norway, Sweden, the United States and Australia, 1964 to 1971/72

50 Ranking of nations according to male-female differences

in age-standardized cause-specific death rates, 1971/72

C H A P T E R 8

51 Hand-rolled cigarettes as a proportion of total adult

cigarette consumption, Australia, 1925-73

52 Comparison of the annual number of cigarettes smoked

per adult in Australia and the United Kingdom (by s e x ) , 1920-73

53 Per capita adult consumption of cigarettes (in l b s ) ,

selected nations, 1920 to 1973

54 Age-sex-specific death rates from the major

cardiovascular diseases at ages 25-44 years, Australia, 1960-62 and 1974-76

55a Sex distribution of patients treated for acute myocar

dial infarction in coronary care units, Australia, 1970 and 1975

55b Age-sex-specific mortality for patients treated for acute

myocardial infarction as a percentage of total admissions Australia, 1970 and 1975

55c Age distribution of patients treated for acute

myocardial infarction in coronary care units, Australia 1970 and 1975

258

261

264-65

269

271

275

279

282

314

315

317

324

328

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56 Per ca p i t a a nnual a dult c o n s u m p t i o n of a l c o h o l i c b e v e r a g e s (in gallons), A u s t r a l i a , 191 0 - 1 1 to

1 9 74-75 333

57 D i s t r i b u t i o n of d r i v e r s and r i d e r s l i c e n c e s by sex,

S o u t h Austra l i a , 1970-75 337

A P P E N D I X B

Bl C o m p o s i t i o n of br o a d cause of d e a t h c a t e g o r i e s used

in the d e c o m p o s i t i o n a n a l y s i s 364

B2 C o m p o s i t i o n of s p e c i f i c ca u s e of d e a t h c a t e g o r i e s 365

B3 P e r c e n t d e c o m p o s i t i o n of the sex m o r t a l i t y d i f f e r e n t i a l

a c c o r d i n g to age and cause of death, A u s t r a l i a , 1910-12 366

a c c o r d i n g to age and cause of death, A u s t r a l i a , 1920-22 367

a c c o r d i n g to age and c ause of death, A u s t r a l i a , 1932-34 368

a c c o r d i n g to age and ca u s e of death, A u s t r a l i a , 194 6 - 4 8 369

a c c o r d i n g to age and cause of death, A u s t r a l i a , 1 950-52 370

BIO P e r c e n t d e c o m p o s i t i o n of the sex m o r t a l i t y d i f f e r e n t i a l

Bll P e r c e n t d e c o m p o s i t i o n of the c h a n g e in the sex m o r t a l i t y

d i f f e r e n t i a l , Au s t r a l i a , 196 5 - 6 7 to 1 970-72 374

B12 S e x - s p e c i f i c s t a n d a r d i z e d d e a t h r ates f rom c o r o n a r y

h e a r t disease, s e l e c t e d nations, 1971/72 375

B13 S e x - s p e c i f i c s t a n d a r d i z e d de a t h r ates from c e r e b r o v a s

c ular disease, s e l e c t e d nati o n s , 1971/72. 376

B14 S e x - s p e c i f i c s t a n d a r d i z e d d e a t h rates f rom m a l i g n a n t

n e o p l a s m of the lung, s e l e c t e d nati o n s , 1971/72 377

B15 S e x - s p e c i f i c s t a n d a r d i z e d d e a t h r ates from bronch i t i s ,

e m physema, and asthma, s e l e c t e d n ations, 1971/72 378

B16 S e x - s p e c i f i c s t a n d a r d i z e d d e a t h r ates from c i r r h o s i s of

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B17

B18

Sex-specific standardized death rates from motor vehicle accidents, selected nations, 1971/72

Life expectancy at birth for the sexes based on recent national mortality experience

380

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LIST OF F I G U R E S

CHAPTER 3

Following Page

1 International form of the medical certificate

of cause of death 72

CHAPTER 4

2 Crude death rate by sex, Victoria, 1861-1911 109

3 Age-sex-specific components of infant mortality,

Victoria, 1863-1911 116

4 Age-specific mortality rates from accidents and

negligence among males, Victoria, 1870-72,

1890-92, and 1910-12 119

5 Maternal mortality in Victoria, 1864-1911 120

6 Age-sex-specific death rates from phthisis,

Victoria, 1910-12 122

CHAPTER 5

7 Ratio of male to female age-standardized death

rates, Australia, 1908-76 127

8 Ratio of male to female age-specific mortality

rates, Australia, 1910-12 to 1970-72 130

9 Percent contributions from mortality differen

tials within broad age-groups to the total gap in life expectancy at birth for the sexes,

successive birth year cohorts, 1870 to 1960 137

10 Age-sex-specific death rates from respiratory

tuberculosis, Australia, 1910-12, 1946-48, and

1970-72 161

11 Maternal mortality in Australia, 1910-75 164

12a Age-sex-specific mortality rates from motor

vehicle accidents, Australia, 1920-22 to

1970-72 171

12b Age-sex-specific mortality rates from all other

forms of external violence, Australia, 1910-12

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C H A P T E R 6

13 Age-sex-specific death rates from motor vehicle acci

dents to persons aged 15-29 years, Australia, 1950-76

14a Age-standardized mortality rates for the sexes at

ages 45-64 years from the major cardiovascular diseases, Australia, 1950-76

14b Age-standardized mortality rates for the sexes at

ages 65 years and over from the major cardiovascular diseases, Australia, 1950-76

15a Age-standardized mortality rates for the sexes at

ages 45-64 years from certain respiratory diseases, Australia, 1950-76

15b Age-standardized mortality rates for the sexes at

ages 65 years and over from certain respiratory diseases, Australia, 1950-76

16a Age-specific mortality rates from malignant neoplasms

of the lung for cohorts of males born between 1875-79 and 1920-24, Australia

16b Age-specific mortality rates from malignant neoplasms

of the lung for cohorts of females born between 1875- 79 and 1920-24, Australia

C H A P T E R 7

17 Sex differential in life expectancy at birth, selected

nations, 1964 and early 1970s

C H A P T E R 8

18 Per capita adult consumption of tobacco in Australia,

1916-75

19 Ownership of motor vehicles and riders and drivers

licences, Australia, 1921-75

223

224

226

228

277

313

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I N T R O D U C T I O N

The changing mortality structure for Western populations during

the course of the 20th century has resulted in marked increases in average

life expectancy. However, this trend has not affected both sexes equally,

with females consistently enjoying greater longevity increments than

males. This widening sex differential has occurred to some extent in

all Western countries, but with variations in both the date of commence

ment and the magnitude of change. In Australia, a female infant born

during the first decade of the century could expect to live about 3.6

years longer than her male counterpart. By the early 1970s, this gap

had widened to 6.7 years, representing a virtual doubling of the female

advantage in longevity over the period.'*’

Differential mortality changes between males and females largely

account for the increasing disparity in the balance of the sexes at the

older ages. According to the 1901-10 life tables for Australia, the

sex ratio of the stationary population at ages 65 years and over was 76

males per 100 females, but by 1970-72, this had decreased to 64 males

for every 100 females, indicating that there are now about 50 percent

2

more women than men at these ages. In a society where marriage is

virtually universal, this would clearly lead to an increasing proportion

of lonely and ageing widows in the community. Thus, on the basis of the

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the proportion of wives who would outlive their husbands increased from 3 64 percent in 1920-22 to 70 percent by the latter date (Young, 1977:288).

The increased economic deprivation that must be sustained by

the society as a result of higher levels of excess male mortality, especi

ally at the working ages, is perhaps the most important economic cost of

this mortality pattern. in 1970-72, for example, approximately one-half

of the male-female differential in life expectancy at birth could be

directly attributed to mortality differences between the sexes at ages

15-64 years, with about one-third of the gap arising from differential 4

mortality at ages 45-64 years alone. Certainly, at this latter stage

of working life, premature male mortality would generally imply a sub

stantial cost in terms of lost productivity, particularly for professional

and managerial workers, since most careers in this sector are, by then,

well established. Additionally, since the majority of deaths at the

older ages usually result from the action of one or more chronic debili

tating agents, it may be expected that many of those who ultimately

succumb to these diseases do so after an extended period of illness,

during which time their economic activity is minimized or often terminated

altogether. Similarly, for many survivors of a motor vehicle accident,

considerable time is spent in convalescence, much of it in institutional

care. Thus, not only is society deprived of potential economic gain as

a result of the current level of morbidity, especially among males, but

simultaneously it must absorb the associated cost of health care.

What is perhaps of greater scientific interest, however, is not

so much the consequences of this trend, but the underlying mechanisms by

which it has arisen. As in any investigation of the differential response

of males and females, one of the more obvious factors which must be

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innate biological difference between the sexes. In fact, this explanation

has been favoured by a number of writers, some, more vehemently 'than

others, suggesting that the greater constitutional weakness of males

becomes more apparent under certain environmental conditions. Others

have proposed that changes in the external environment, perhaps mediated

by these biological constraints, have worked more to the relative detri

ment of males. Advances in medical technology and improved public health

measures have combined to essentially eliminate the infectious diseases

in the developed countries, and in the case of maternal mortality, this

change has obviously worked to the exclusive benefit of females.

Conversely, working conditions, and in particular, industrial safety,

have undoubtedly improved during the 20th century, which, given the

traditional division of roles between the sexes, could reasonably be

expected to reduce the mortality of males more than that of females. One

might also suspect that changes in lifestyle, with the adoption of

certain habits and practices, especially by men, have almost surely

proved an impediment to potential extensions of the lifespan.

It is the purpose of this study to delineate the intricate

network of age and cause of death contributions to the changing sex

mortality differential in Australia, and to explore the possible causa

tive processes underlying this trend. The study was inspired by, and

has frequently drawn on concepts developed in the recent comprehensive

works on the subject by Preston (1970; 1976) and Retherford (1975). The

present investigation may be viewed as an extension of these studies in

that it traces the development of the differential in mortality between

the sexes in Australia from the origins of settlement, and, in this

sense, provides perhaps a more complete historical case study of this

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The thesis itself may be conveniently described in three parts.

In the first, the widening sex differential in mortality is defined for

Australia against a backdrop of previous studies dealing with this aspect

of differential mortality, both from the point of view of demographic

characteristics, and the postulated social, behavioural, and biological

changes that might have influenced this pattern. Further, in this

section, the recognition that all trends and differentials in the mortality

of human populations must necessarily result from the impact of the

underlying cause of death structure is implied through an examination of

the accuracy and comparability of cause of death statistics.

The second section deals exclusively with the differential

mortality of males and females in Australia. Firstly, the changing sex

ratio of the population is examined and the factors affecting mortality

during the period of colonization are discussed in terms of their impact

on the relative survival of the sexes. A second chapter, which also

introduces some of the basic methodological concepts utilized in the

study, concentrates mainly on changes in the sex pattern of mortality

during the first half of the 20th century. Although the political

federation of Colonies to form the Commonwealth of Australia was actually

effected in 1901, mortality data for all States together were not

available in a convenient form until 1908. Hence, in order to continue

with the practice of performing the analysis for the three-year period

around the census date only, the next immediate census -year, i.e. 1911,

was selected as the base for the initial period for assessing the pattern

of change for Australia as a whole.

Data considerations also largely determined the period of

investigation according to a more refined cause of death format. In as

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specific morbid conditions in the changing mortality of the sexes,

comparability problems for a number of major disease entities precluded

any such analysis before 1950, the year that the much altered Sixth

Revision of the International Classification of Causes of Death was first

introduced into Australia. Thus a third chapter dealing with the pattern

of mortality change for the sexes in Australia since 1950 provides a

more specific analysis of the causes of death responsible for this trend.

The third and final section places the Australian experience

in an international perspective, and simultaneously offers some discussion

about the likely contribution from selected factors related to individual

lifestyle and the environment to this mortality pattern. Where relevant

data were not available for Australia, the possible impact of certain

behavioural tendencies on the relative survival of the sexes was assessed

through an inferential approach using the experience of other nations

where similar mechanisms had previously been investigated.

Essentially, the thesis is an analytical study of the differential

mortality of the sexes in Australia, with special reference to the impact

of the changing cause of death structure as determined by certain social,

medical, and behavioural factors. The overall aim of the study is to

contribute to the understanding of male-female differences in mortality

in the developed world, and to provide some insight into the role of

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FOOTNOTES

1. Calculated from Official Life Tables for Australia.

m f

2. Computed as T 65/T65, where the life table parameter Tx represents

the number of person-years lived by the synthetic cohort at ages 65 years and over, and the superscripts m and f refer to the mortality experience of males and females respectively.

3. Based on a mean age of first marriage for males and females of 29

years and 25 years respectively in 1920-22, and 26 years and 23 years respectively in 1960-62 (Young, 1977) .

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R EV IE W OF THE L I T E R A T U R E R E L A T I N G TO THE SEX

D I F F E R E N T I A L IN M O R T A L I T Y

B A C K G R O U N D

Previous investigations of the differential mortality of the

sexes have tended to emphasize two basic themes. One is concerned with

the identification and description of sex patterns of mortality according

to certain temporal and demographic variables. A complementary approach

places greater emphasis on the underlying biological and environmental

influences on mortality which are thought to reduce the chances of

survival of one sex over the other. Accordingly, the present review,

which begins with a brief account of historical references to the topic,

will examine the relevant literature on the basis of whether the study is

primarily descriptive, or, in addition, if it gives some consideration to

the role of possible causative factors in this mortality pattern.

Traditionally, females have generally been viewed as both

physically and emotionally inferior to males. The disciple, Peter, for

example, writing in the first century, decreed in his first Epistle that

men should be considerate towards their wives, 'bestowing honour on the

woman as the weaker sex'. A similar view was held even as late as the

Renaissance period, as is evidenced by the impassioned plea of Shakespeare's

Hamlet, 'Frailty, thy name is woman'.

However John Graunt's foundation work on the statistical study

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and not females, experienced the higher mortality. From the records of

the London parishes, he observed that although women were more likely than

men to suffer ill-health, their overall level of mortality remained below

that of males. This, lie suggested was probably due to the fact that

physicians were successfully treating many of their female patients, who

commonly suffered from such illnesses as "Breedings, Abortions, Child

bearing, Sore-breasts, Whites, Obstructions, Fits of the Mother, and the

like", or else "men, being more Intemperate than women, die as much by

reason of their Vices, as women do by the Infirmitie of their Sex"

(Craunt, 1662:59).

During the 18th and 19th Centuries, a number of studies appeared

on the causation and extent of sex differences in health and longevity.

Some of these authors attributed the higher mortality of males to their

deleterious work habits (Moheau, 1778) and the "incessant contingencies

which the males are more obnoxious to both by land and water than the

females" (Maitland, 1739). Not all writers, however, subscribed to

what would nowadays be labelled as the 'environmental* explanation. Some,

like Quetelet (1835), argued that the higher death rate of males during

infancy was probably more a result of inherent biological differences

between the sexes than of any external influences which might disadvantage

males over females. More specifically, Clarke (1786:353) considered

that the larger average size of male foetuses was responsible for their

higher incidence of still-births, and moreover, consequent injuries

sustained during the birth process rendered the male "more apt to be

affected by any exciting cause of disease soon after birth and less able

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S E X P A T T E R N S O F M O R T A L I T Y D U R I N G T H E 2 0 T H C E N T U R Y

The Changing Sex Mortality Differential

As early as 1938, the widening disparity in the survival

experience of the sexes was noted for the United States by Wiehl (1938)

who observed that the male-female difference in age-adjusted death rates

had steadily risen since the turn of the century. In fact, since the

early 1920s, the rate of divergence had begun to accelerate. An

investigation of the relative age contributions to this widening differ

ential revealed that the increasing excess mortality of males was mostly

determined by their rising death rates during middle life, and to a

lesser extent, by the greater reductions in the mortality of females

during infancy and early childhood. When compared to the experience of

a number of other Western nations around the mid-1930s, the United States

exhibited the greatest overall disparity in the relative survival of the

sexes, particularly for young adults aged between 25 and 44 years.

A similar trend for England and Wales was reported by Martin

(1951) who examined the differential mortality of the sexes within 'natural*

age groups for the centenary commencing in 1841. Male mortality during

the first year of life had always exceeded that of females, but the

mortality sex ratio had remained relatively constant for infants until the

turn of the century, when a gradual rise in the measure was observed."^

This change in the s:ex pattern of infant mortality occurred about the

same time that the general level of mortality in the first year of life

began to fall, prompting Martin (1951:291) to conclude that "the size of

the mortality sex ratio seems to be some function of the size of the

infant mortality". Essentially the same pattern was evident for the

childhood years where the ratio gradually increased during the 1920s, mostly

due to the larger declines in mortality for females from the digestive

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The sex mortality differential during late adolescence and

early adulthood began to widen in England and Wales shortly after the

commencement of the 20th century. Tuberculosis, traditionally the most

important cause of death during this stage of the life cycle, had a

relatively low sex differential and declines in this disease appeared to

have little effect on the overall movement of the sex mortality ratio at

these ages. According to Martin (1951), however, the most important

trends affecting the sex pattern of mortality for the 15-24 year olds

were the not inconsiderable declines in mortality from maternal causes and

the rapid increase in violent deaths among young men. For ages beyond 25

years, the ratio of death rates between the sexes increased with advancing

age over the period for all but the highest ages, with the changes in the

cause of death structure underlying these trends reflecting the increased

susceptibility of males to the various morbid conditions common to adult life.

An attempt was also made to compare the mortality of men and

women on the basis of the occupations of all men, both married and single,

and the corresponding categories of married women classified according to

their husbands' occupation. However, Martin (1951) reported that the

mortality sex ratio varied quite considerably between occupations within

selected social class categories; consistent trends, either in excess of,

or below the respective social class average, were rare.

An interesting paper by Hocking (1952) appeared in the Journal

of the Institute of Actuaries where he investigated the validity of a

popular theory, then being advanced as a possible explanation of the

deceleration in the rate of decline of adult male mortality in England and

Wales. The proponents of the theory, known as the 'burnt-out veterans’

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many of their fittest members during the 1914-18 war, and many of those

who survived later suffered from "delayed and cumulative after effects"

(Hocking, 1952:354). This, it was suggested, would consequently inflate

their death rates. Although there was some empirical support for this

proposition from a period analysis of mortality rates, when Hocking

arranged the data in cohort form, he found that the male/female mortality

ratios for persons aged 20-39 years in 1916 were consistent with trends

expected on the basis of the experience of neighbouring cohorts.

While conceding that part of the emerging sex mortality

differential during adult life could be explained by the theory, Hocking

considered that the number of war pensioners was too small to have any

significant effect on male mortality rates at these ages. Rather, he

attributed the trend to a persistent widening in male-female death rates

from bronchitis and the circulatory diseases between 1931-32 and 1949-50,

2

a result, he suggested, of "the stress of modern life" (Hocking, 1952:361).

With increasing interest in the subject of sex differentials

in mortality, a number of generalizations of the phenomenon began to

appear. It was popularly held that inferior male longevity had prevailed

throughout the 19th and 20th centuries, and departures from the age

pattern of higher female survival ratios normally involved only the

child-bearing ages. Stolnitz (1956) investigated these hypotheses using

historical data on age-specific survival ratios, and reported that lower

female mortality at all ages had obtained in the Western world only

since the 1930s, and in non-Western Europe certainly not before the close

of the inter-war period. Moreover, he noted that although higher female

mortality would most likely occur in the child-bearing ages, the

(34)

century Western populations, Stolnitz observed that over one-half of

the recorded excess morality of females took place between the äges of

7 and 12 years, and even by the age of 17 years, higher female mortality

was more common than at later stages of child-bearing where fertility was

much higher.

The precise manner in which the complexity of sex differences in

mortality at various stages of life translates into a longevity different

ial very much depends on the overall structure of the age schedule of

mortality. Since higher female death rates normally only occur at those

ages where mortality itself is relatively light, the extent of sex

differences in survival at the older ages, where females typically enjoy

a considerable advantage over males, might be expected to exert an over

riding influence on the ultimate size of the longevity differential

between the sexes.

Stolnitz (1956), in fact, found that this was indeed the case

in the West where greater female longevity at all ages had been almost

universal since the 1840s. The only outstanding departure from this

pattern was Ireland where superior male longevity was recorded in the

1920s over an appreciable range of ages. At any rate, he reported that

since 1930 no Western life table on record showed higher male longevity

at any age up to 70 years, and his analysis for non-Western Europe

indicates that longevity differentials were consistently in favour of

females since about the same time. This is not to deny, of course, that

higher male longevity was uncommon. On the contrary, as Stolnitz (1956)

points out, the life expectancy of males quite possibly exceeded that of

females at some ages in non-Western Europe prior to World War I, and

longevity differentials favouring males have apparently persisted in

(35)

An examination of trends in the longevity differential between

the sexes led Stolnitz to conclude that persistent increases in this

measure had been almost universal in the West since the early decades of

the 20th century, and by 1950, had widened to a level previously

unrecorded in Western societies. Moreover, most Western differentials

between the ages of 50 and 70 years had rapidly increased during the 1930s

and 40s, and had continued to rise into the mid-1950s. Interestingly

enough, Stolnitz himself did not attempt an explanation of these trends,

but rather suggested that the reasons for them should "merit far more

investigation than they have received to date" (Stolnitz, 1956:26).

Sex differentials in longevity for countries of South Asia have

also been investigated by El-Badry (1969), who sought an explanation for

the high population sex ratios observed in these cultures. He proposed

that apart from mortality differences, an unusually large number of

males in the population might result from three additional socio

demographic factors; an abnormally high sex ratio at birth, larger

relative emigration of females or higher immigration of males, and

relatively larger underenumeration of females. He found little empirical

support for the first two propositions and available evidence indicated

only a marginal effect from the third. Given that the differential

mortality of the sexes was the most important determinant of the sex ratio

in these populations, he reported a higher death rate for females

throughout childhood and the child-bearing ages, with little difference

3 between the rates for the sexes beyond age 45 years.

In addition, using Ceylonese data for the decade 1953-63, El-Badry

observed that the ratio of female to male mortality rates at ages 15-44

years fell by some 22 percent due to a considerable reduction in mortality

(36)

significant decrease of about 8 percent in the ratio for children aged

5-9 years, acted to reduce the male advantage in life expectancy' at

birth from 1.6 years in 1950 to 0.5 years by 1960-62. Due to a complexity

of factors, however, El-Badry was reluctant to predict whether or not a

similar trend might be observed in India and Pakistan where the level of

mortality in the late 1960s was thought to be comparable to that observed

in Ceylon 20 years before.

Sex Differences in Mortality by Cause of Death

The magnitude of the sex mortality differential at a particular

point in time depends, of course, only on the age pattern of mortality

differences between the sexes. This basic age pattern, however, is

itself determined by male-female differences in the cause of death

structure. Consequently a detailed investigation of the differential

response of the sexes to the action of various morbid conditions should

permit a further insight into the overall mortality pattern between

them.

Ciocco (1940a) examined the importance of certain broad cause

of death categories for the sex mortality differential using crude

cause-specific death rates computed for the white population of the United

States Registration Area in 1930. By far the largest differential between

the sexes was observed for diseases of the circulatory system. Death rates

from the respiratory diseases and maladies of the nervous system also

displayed high masculinity ratios, but for only one category, endocrinal

disorders, was the crude mortality rate for female in excess of that

observed for males. Essentially the same pattern emerged when only those

conditions reporting at least 1,000 male or female deaths in 1930 were

(37)

death rate. A finer examination of cause-specific mortality rates,

expecially for the circulatory and respiratory diseases, prompted Ciocco

(1940a:73) to conclude that this male overmortality probably resulted

from disorders attributable to "the social function of the sex", although

in a sequel to this paper, he further implicated "inherent biological

constitution" as a possible etiological factor in the differential

susceptibility of men and women to these diseases (Ciocco, 1940b:196).

Ciocco’s (1940a) findings were derived on the basis of crude

cause-specific death rates only, and thus should be viewed with some

caution since the influence of differential age structures between the

sexes on the cause of death pattern have been ignored. In his second

paper, however, he attempted to control for these age distortions by

examining the impact of the various diseases within broad age groups.4

It is worthwhile noting that the more detailed age analysis only served

to reinforce his conclusions about the importance of the circulatory and

respiratory diseases in the determination of the gap in survival between

the sexes. In particular, he reported that higher male mortality from

the circulatory diseases was especially obvious during infancy, where

congenital malformations of the heart were primarily responsible, and in

later life, when the impact of the degenerative heart diseases became

more apparent.

Commenting on the age pattern which he observed for the respiratory

diseases, Ciocco (1940b:194) concluded that

Altogether, the sex differences among deaths from causes demonstrating a breakdown of the respiratory system follow the same age pattern as those from diseases of the

circulatory system. The highest differences occur at the

two extreme age groups.

A closer examination of specific disease mortality within this broad

(38)

from the infectious respiratory conditions than did males. Consequently,

the higher overall male mortality from respiratory diseases was1 largely

the result of their "greater liability to a break-down of the lungs

proper" (Ciocco, 1940b:194).

Ciocco's identification of significant sex differences in

mortality for the circulatory and respiratory diseases was later substan

tiated by a series of studies dealing with trends in the sex pattern of

mortality from these causes. The first such investigation of interest

here was a study of race and sex differences in cardiovascular-renal

mortality in the United States between 1920 and 1947 by Moriyama and

Woolsey (1951). For the category as a whole, they noted that death rates

for white males aged 35-64 years had actually increased over the period,

in marked contrast to the considerable reductions observed for white

females of the same age. An examination of trends for selected sub

categories revealed that sex differences in mortality from diseases of

the heart, particularly those certified as due to angina pectoris and

coronary disease, were largely responsible for this pattern. A

similar, but less significant tendency was also reported for death rates

from all forms of nephritis, while differential mortality trends from

intracranial lesions of vascular origin were considered inconsequential.

The recognition that these mortality trends might well

represent the manifestation of a differential sex response to some

external factor or set of factors motivated a further study by Kaufman

and Woolsey (1953) in which they investigated mortality trends for some

additional causes of death. Two factors suspected of influencing the

sex differential in mortality from the major cardiovascular-renal

(39)

implicated as possible etiological agents in mortality from two other

chronic conditions studied by the authors, diabetes mellitus and ulcers

of the stomach and duodenum. A third condition, intestinal obstruction

and hernia, was included in the analysis mostly as a ’control’ category,

although deaths from this cause were also considered to be marginally

dependent on obesity and tension.

Changes in age-specific death rates were compared for the four

disease categories according to mortality levels in 1921-26 and 1942-47

for the white population of the United States. For the cardiovascular-

renal diseases and ulcers, modifications to the sex pattern of mortality

were quite similar. Death rates for males increased throughout the age

group 25-74 years, whereas for women, mortality declined at all ages

from 25-84 years with the rate of decline decreasing with advancing age.

The trends for the remaining causes of death were less precise. Diabetes

declined in importance for both sexes at the younger ages, but beyond age

65 years, both males and females experienced comparable increases in

mortality from this disease. According to Kaufman and Woolsey (1953:766),

this latter trend reflected the deferment of death for many diabetic

patients to the older ages and an improvement in diagnostic knowledge about

the condition. Reductions in mortality from intestinal obstruction and

hernia for females aged 45 years and over were in excess of those reported

for males, although the contribution from this differential trend was

somewhat smaller than that derived from changes in mortality from the

cardiovascular-renal disorders and ulcers.

By way of summary, Kaufman and Woolsey (1953) considered that

the evidence from these trends was probably not sufficient to suggest an

association between the two factors under study and mortality differentials

(40)

investigation of the relationship between certain psychosomatic factors

and mortality from cardiovascular-renal diseases might prove "a-parti

cularly interesting possibility" (Kaufman and Woolsey, 1953:767).

Reporting on the changing pattern of mortality from lung

cancer and the chronic respiratory diseases in the United States between

1930 and 1959, Dorn (1961) noted a persistent widening in the differential

between the sexes beyond the age of 40 years. Although the disaggrega

tion into specific trends for the various respiratory conditions was

impeded by frequent misclassification of these disorders, Dorn considered

this to be a real trend, due mostly to differential mortality changes

from bronchitis, emphysema, and allied conditions. In addition, he

reported that both sexes had benefited from substantial declines over

the period in deaths from respiratory tuberculosis and pneumonia, even

though for the latter cause, mortality rates for both sexes had essenti

ally stabilized during the 1950s.

Up until this point, the basic methodology reviewed for

investigating male-female differences in mortality has centred around an

examination of sex differences in age-cause-specific death rates. A

method of summarizing the total variation in these rates in terms of a

few ’principal components’ of mortality was first developed by Ledermann

and Breas (1959) and later extended by Bourgeois-Pichat (1963) to

include the action of two additional components, one of which reflected

the impact of sex differences in mortality on the overall survival

5 pattern.

Data from twenty-six low mortality countries for three time

periods embracing immediate pre- and post-war experience, and the latter

part of the 1950s, were subjected to factor analysis in a slightly modi

(41)

affecting males formed the 'fifth* component in Bourgeois-Pichat's

analysis, and any influence which this component might have had.on female

mortality was deliberately ignored.^ (Actually the effects for females

were included with the first three components and consequently the

fifth component should not be viewed as a 'pure' component as is

generally understood in factor analysis.) In order to facilitate com

parisons between countries and within countries over time, the effects

of the various components were computed within the broad age intervals,

under 1 year, 1-4 years, 5-34 years, 45-64 years, and 70-84 years. In

general, the action of the components beyond the first was to reduce the

first component expectation of life, although in all cases, the not

effect of these other components was small in relation to the dominant

influence on mortality from the first component.

The greatest impact of the fifth component on mortality was

felt at ages 5-34 years and 45-64 years. There were also some further

effects from this component at ages 70-84 years but this contribution

was negligible compared to the action of the third component at these

ages. According to Bourgeois-Pichat, the fundamental determinant of the

importance of the fifth component at ages 5-34 years was the high

masculinity ratio of deaths from violence. He noted that variations in

female death rates from violent causes had little effect' on this component,

and moreover, when mortality from causes of death other than violence was

relatively high at these ages, the effects of the fifth component were

slight. However, as soon as mortality from non-violent deaths began to

decrease, the effects of this component became more and more apparent

corresponding to increases in the masculinity ratio of violent deaths.

It was for the age group 45-64 years, however, that the action

Which is the weaker sex? : A study of the differential mortality of males and females in Australia

MORTALITY OF MALES AND FEMALES IN AUSTRALIA

ALA N D. L OP E Z

ABSTRACT

TABLE OF CONTENTS

A C K N O W L E D G E M E N T S

A B S T R A C T

v

T A B L E OF C O N T E N T S

LIS T OF T A B L E S

x i I i

L IS T OF F IG UR E S

C H A P T E R 1

I N T R O D U C T I O N

1

C H A P T E R 2

R E V I E W OF THE L I T E R A T U R E R E L A T I N G TO T HE SEX

7

D I F F E R E N T I A L IN M O R T A L I T Y

C H A P T E R 3

A C C U R A C Y A N D C O M P A R A B I L I T Y OF DATA ON CAU SE OF DEATH

53

C H A P T E R 4

M O R T A L I T Y O F T H E S E X E S IN A U S T R A L I A , 1 7 8 8 - 1 9 1 1

89

C H A P T E R 5

I M P A C T O F C H A N G E S IN T H E C A U S E O F D E A T H S T R U C T U R E

O N T H E S E X M O R T A L I T Y D I F F E R E N T I A L IN A U S T R A L I A

1 2 7

C H A P T E R 6

A N A L Y S I S O F S E X M O R T A L I T Y P A T T E R N S IN A U S T R A L I A S I N C E

1 9 5 0 A C C O R D I N G T O S T A T E D C A U S E O F D E A T H

1 7 8

C H A P T E R 7

I N T E R N A T I O N A L C O M P A R I S O N O F T R E N D S A N D D I F F E R E N T I A L S

IN T H E R E L A T I V E M O R T A L I T Y O F T H E S E X E S

2 3 4

C H A P T E R 8

D I S C U S S I O N O F F A C T O R S R E L A T E D T O T H E D I F F E R E N T I A L

M O R T A L I T Y O F T H E S E X E S

2 9 1

APPENDIX A

METHODOLOGICAL CONCEPTS

APPENDIX B

SUPPLEMENTARY TABLES

APPENDIX C

LISTING OF FORTRAN PROGRAMS

C H A P T E R

C H A P T E R

4

C H A P T E R

LIST OF T A B L E S

C H A P T E R 5

C H A P T E R 6

C H A P T E R 7

C H A P T E R 8

LIST OF F I G U R E S

C H A P T E R 6

C H A P T E R 7

C H A P T E R 8

I N T R O D U C T I O N

FOOTNOTES

R EV IE W OF THE L I T E R A T U R E R E L A T I N G TO THE SEX

D I F F E R E N T I A L IN M O R T A L I T Y

B A C K G R O U N D

S E X P A T T E R N S O F M O R T A L I T Y D U R I N G T H E 2 0 T H C E N T U R Y